ANN ARBOR—University of Michigan researchers are helping to usher in “a new era” of medicine. Patients could soon receive individualized drugs and treatments based on their genetic makeup rather than on an average prescription for an average patient.

“We may, at some point, have genetics-specific medicine for people,” says Rowena Matthews, the G. Robert Greenberg Distinguished University Professor of Biological Chemistry and senior research scientist in the Biophysics Research Division at U-M. Her research, which aids in understanding the clinical implications of one type of common human variation, is published in the Dec. 11 issue of the Proceedings of the National Academy of Sciences.

Matthews, her postdoctoral fellow Kazuhiro Yamada, and her collaborators Zhoutao Chen and Rima Rozen from McGill University in Montreal, studied the impact of a common mutation in the human genome sequence. The C677T mutation affects an enzyme, methylenetetrahydrofolate reductase (MTHFR). A lack of the vitamins folic acid or riboflavin can lead to the inactivation of MTHFR, and the researchers have shown that humans with the C677T mutation may be particularly susceptible to such vitamin deficiency. Inactivation of MTHFR results in elevations in a compound called homocysteine. Such elevations may lead to increased risk of heart disease, strokes, and birth defects in humans.

“About 15 percent of all Americans may be particularly vulnerable to folic acid or riboflavin deficiency,” says Matthews, “because they inherited the C677T mutation from both parents.” This means they could be more at risk for heart attacks or for birth defects in their offspring if they receive inadequate dietary supplies of these two vitamins. But this recent research shows that these nutritional deficiencies should be “very easy to fix,” says Matthews. Increasing the intake of riboflavin and folate through better diets and vitamin supplements should help prevent these potentially life-threatening problems in people at risk.

“We now need to see if increasing folic acid and riboflavin intake in at-risk patients really does reduce cardiac risk,” says Matthews. “We also need to learn what advantages the C677T mutation provides for humans.” Matthews says that any common mutation that persists in the human population must confer advantages as well as disadvantages. If the mutant had an entirely negative influence, it would have been eliminated. Research from the laboratory of Matthews’ collaborator, Rima Rozen, suggests that the C677T mutation may confer protection against some forms of cancer, provided the patient has an adequate dietary intake of folic acid. Scientists must look at ways to avoid the disadvantages associated with this variation, while maximizing the advantages.

EDITORS: For more information on Matthews’ research sign on to the Web site, pnasnews@nas.edu or call the PNAS news office at (202) 334-2138. Contact Rowena Matthews at (734) 764-9459 or at rmatthew@umich.edu.

Rowena MatthewsRima Rozenpnasnews@nas.edu